Picture is showing damage made by using tuttle box fin into deep tuttle box board. Yellow arrows are showing the crack made by the fin base. When you are fixing the fin into the board you are applying force with tightening the screws and the fin base is pulled inside the board. This way, the fin is pushing into front and back of the box. The blue arrow is showing the direction of the force and as a consequence the box is cracked. Water is entering and we all know the scenario. Red arrow is showing the deepest point of tuttle base into deep tuttle box. This is also the point where the crack ends.